Fiber-reinforced resin substrate, integrated molded article, and method for manufacturing fiber-reinforced resin substrate

A fiber-reinforced plastic substrate comprising components [A], [B′], [C′], and [D] shown below:

• [A] reinforcing fibers;
• [B′] thermoplastic resin (b′);
• [C′] thermoplastic resin (c′);
• and
• [D] thermosetting resin (d),
• wherein
• a resin area (B′) including the component [B′], a fiber-reinforced plastic area (E) including the component [D] and the component [A], and a resin area (C′) including the component [C′] are adjacent in this order to form boundaries, and
• the component [B′] and the component [C′] satisfy formula (3):
• 2<ΔSP≤10 Formula (3)
• wherein
• ΔSP is an absolute value of difference between SPa and SPC;
• SPa is an SP value of the component [B′] [(MPa)1/2];
• and
• SPc is an SP value of the component [C′] [(MPa)1/2].

A method for producing a fiber-reinforced plastic substrate including components [A], [B], and [C] shown below:

• [A] reinforcing fibers;
• [B] thermoplastic resin (b);
• and
• [C] thermoplastic resin (c),
• wherein
• at least a drawing step, a first impregnating step, and a second impregnating step shown below are carried out continuously in this order while causing the component [A] to travel:
• <drawing step> a step of obtaining a continuous reinforcing fiber sheet in which the component [A] is arranged in one direction by aligning the continuous component [A], and then supplying the obtained continuous reinforcing fiber sheet including the component [A] in a fiber direction toward a subsequent step;
• <first impregnating step> a step of impregnating the component [B] from one surface of the continuous reinforcing fiber sheet to obtain a fiber-reinforced plastic intermediate in which the component [B] is present on a first surface of the continuous reinforcing fiber sheet;
• <second impregnating step> a step of impregnating component [C] from a second surface opposite to the first surface to obtain a fiber-reinforced plastic substrate, and
• a distance Ra(bc) between Hansen solubility parameters of the component [B] and the component [C] satisfies formula (5):
• Ra(bc)={4(δDB−δDC)2+(δPB−δPC)2+(δHB−δHC)2}1/2≥8 Formula (5)
• wherein
• Ra(bc) is a distance between Hansen solubility parameters of the component [B] and the component [C];
• δDB is an energy due to intermolecular dispersive power of the component [B];
• δDC is an energy due to intermolecular dispersive power of the component [C];
• δPB is an energy due to intermolecular dipole interaction of the component [B];
• δPC is an energy due to intermolecular dipole interaction of the component [C];
• δHB is an energy due to intermolecular hydrogen bonding of the component [B];
• and
• δHC is an energy due to intermolecular hydrogen bonding of the component [C].